Electric reversing device for tapping machines



Aug. 23, 1927.

B. s. T. BISHOP ET AL ELECTRIC REVERSING DEVICE FOR TAPPING MACHINESFiled Jan. 13. 1926 jam (D6782 97-6 3 #5. T B'Gabop Rrc 154422742? Dow:T 1: I as a iis iiii??? I I I i' 'etented Aug. 23, 1927.

' where the tap has to be turned into the.

v .UNlTED STAT PATENT, OFFICE.

BENJA IN S. '1. msnorpor SHREWSBURY, Ann PERCIVAL E. now, OF LEICESTER,MASSACHUSETTS, ASS'ICNORS To LELLAND-GIFFOBD COMPANY, OF WORCESTER,

MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

ELECT RIC REVERSING DEVICE FOR TAPPING-MACHINES.

This invention relates to an electric reversing device, for useparticularly in a tapping machine, where a spindle has to be rotated andfed in one direction and then fedback, and where it is desired tocontinue the operation automatically.

, The principal objects of the invention are to provide a device of thiskind which will consist of few parts and therefore be comparativelyinexpensive to manufacture, and which will operate with certainty alarge number of times without requiring resetting. Improvements indetails of construction and arrangements of parts also constitute afeature of the invention.

Reference is to be had to the accompanying drawings, in which Fig. 1 isa front view of a part of a tapping machine with a switch constructed inaccordance with this invention applied thereto and shown in centralsection;

Fig. 2 is a front view of one of the switch connections, as indicated bythe arrow 2 in Fig. 1, but Showing the movable member slightly separatedfrom the stationary member;

Fig. 3 is a general side view of the device, and

Fig. 4 is a diagram of the electrical connections.

The invention is shown as applied to a, machine having a motor enclosedin a casing 10 and a spindle 11 concentric therewith,

in which spindle a tool, as a drill or tap,

can be applied in the usual manner. No tool is shown in the drawings,but this invention is particularlydesigned for use in tapping.

.. workin accordance with the thread and then drawn out in the same way,and the.

electrical connections have to be reversed at each end of the Stroke.Therefore, the spin dle 11 will travel up and down as it rotates in anon-rotatable quill 9 fixed so as to reciprocate with the spindle. Onthis is fixed a collar 12 movable with the spindle, and connected withit a bracket 13 on which is mounted the bottom of a vertical rod 14.This vertical rod therefore goes up and down with the spindle. On therod near the bottom and top are two collars 15 constituting. stops.These stops may be adjusted in any desired manner but I have shown themas held by screws and thumb drawings.

nuts 16 having four arms. They are shown ,as of well known constructionso that they can be tightened upon the rod to fix the collars for thepurpose'of controlling-the vided with openings for the rod and, in

fact, ,acts as a guide for it, as the rod is supported only at thebottom. At the top and bottom of this casing 20 are two oppositelyarranged bell cranks 21 one arm of each of which is horizontal and is inthe form preferably of a yoke partly surrounding the rod 14 and inosition to be engaged b the stops 15 w en the rod moves up or (own tolimit the feed of the tap or its withdrawal. Each of these bell cranksis pressed forward bya spring 22 and its end is in the form of a hookwhich is adapted to engage one of a pair of projecting flanges 23 on atubular slide 24 which is slidabl mountedon a tube 25 that surrounds andts the rod 14. At each end of this tube 25 it is adaptedto engage theother projecting end or yoke of one of the bell cranks 21. It isprovided with a screw collar 26 at each end of the same size as thesliding collar 24. There are two springs 27 coiled around the tube 25each extending from the collar 26 to the slide 24.

The slide 24 has pivoted to it a lever 30. This lever is pivoted at theend on a stud 31 onv the box or casing 20. It carries a head 32 having aplurality of electrical contacts 33, four, in number as shown in theseend carryin the head 32 by a spring pin 34 and is yieldingly held inneutral position by springs 35. Therefore, the contacts come intoengagement yieldingly with corresponding-electrical contacts 37 on oneor the other of a pair of heads 38.

The details of this switch need not be described as it is designed tooperate in accordance with the diagram shown in Fig. 4 for the purposeof "sending the current through the motor from the feed lines, first inone direction and then in the other. Thus the spindle 11 is turned andmoved forwardly through the article to be tapped in a helical manner andthen withdrawn in The lever 30 has a yoke. at its.

the same mannerand the operation repeated automatically over and over.The usual speed control device 40 is shown connected with the box 20, asalso indicated in the diagramKFig. 4), to show the connection of thisdevice with the rest of the machine, but the invention does not involvethis feature.

Now while running, the parts are in one extreme position with one set ofcontacts closed and one spring 27 holding. the slide 24. When one of thestops 15 comes, either from above or below, and engages one of the yokesof the bell cranks 21, it will push that yoke inwardly, compress thecorresponding spring 22 and draw the hook on the bell crank out awayfrom theflange '23 on the collar 24. At this time the stop whichvhasperformed this functionvwill press on the end of the tube 25 through thebell crank end and the spring will force the sliding collar 24 along thetube 25 by yielding pressure. This will force the slide 2A to a positionin which the other bell crank will snap over the other flange 23 at theother end of the slide and lock it in its other extreme position, asshown at the top in Fig. 1. As the slide moves, the switch is reversed.-

Although we have illustrated and described only a single form of theinvention we are aware of the fact that modifications can be madetherein by any person skilled in' the art without departing from thescope of the invention as expressed in the claims. Therefore we do notwish to be limited in this respect but what we do claim is 1. In anelectric current reversing device, the combination with a movablespindle, and a rod connected with the spindle to move with it andlocated parallel with it, of a pair of stops adjustable along the rod, adouble flanged slide slidable along the rod, means in position to beengaged by the stops as the rod moves for holding said flanged slide andadapted when enga ed by either stop to release the flanged side,yielding means on opposite sides of the slide for changing its positionwhen it is thus released, and an electric switch connected with saidslide to be operated by its movement for breaking the circuit andconnecting it in another way.

2. In 'an, electric current reversing device, the combination with amovable spindle, and a rod connected with the spindle to move with itand located parallel with'it, of a 'tube'slidable on the rod, a pairof-stops adjustable along'the rod at opposite ends of the tube, a doubleflanged slide slidable along the rod, means at the ends of the tubeprojecting over the rod and in position to be engaged by the stops asthe rod moves for holding said flanged slide and adapted, when engagedeither stop. to release the flanged slide, yielding means on oppositesidesof the slide for changinr its position when it is thus released,and ,an electric switch connected with said slide to ,be operated by itsmovementfor breakingthe circuit and connectingitin another wav.

3. In an electric current reversing device, the combination with areciprocable rotatable spindle, of a rod connected with the spindle toreciprocate with it. a pair of stops adjustable alongthe rod, a flangedtubular slideisurrounding the rod, means in position to be engagedby thestops as the rod moves for engaging the flange of said slide and adaptedwhen engaged by either stop to release the flanged slide, and a switchconnected with said slide so as to be operated by its movement forbreaking and making the circuit. v

4. The combination with a tapping ma chine having a. rotatable andreeiprocable spindle, of a rod parallel with the spindle and mounted tomove longitudinally but not circumferentially with it, a reversing bjoxmounted in stationary position on the machine having a passage throughit for the rod, a slide movable along the rod, yielding means for movingthe slide in either direction, a pair of latches for engaging theopposite ends of said slide alternately, means whereby when the rodmoves to a limiting position, one of the latches will be released toallow the slide to move in the opposite direction, and means connectedwith the slide for reversing the electric current.

In testimony whereof we have hereunto affixed our signatures. I

BENJAMIN S. T. BISHOP.v PERCIVAL E. DOW.

Seal;

CERTIF I GATE. OF CORRECTION Patent No. 1,640,177. Granted August 23,1927.

BENJAMIN S. T. BISHOP ET AL.

It is hereby certified that the name .of the assignee in the above.mlmbered patent was erroneously written and printed as "Lelland-GiffordCompany". whereas said name should have been written and printed as"Leland-Gifforil Company", as shown by the records of assignments inthis office; not! that the said Letters Patent should be realwith thiscorrection therein that the same may conform to the record-of the casein the Patent Office.

Signed and sealed this 4th day of October, A. D. 1927.

4 M. J. Moore, Acting Conmiuioner of Patente.

L-A4A

